Molecular phylogeography of Rosenberg's goanna (Reptilia: Varanidae: Varanus rosenbergi) and its conservation status in New South Wales

Rosenberg's goanna, Varanus rosenbergi, is listed as 'Vulnerable' in New South Wales, but it is not currently listed nationally in Australia as large populations exist on Kangaroo Island in South Australia. There are several significant morphological and behavioural differences between populations in NSW and those in the rest of Australia and some researchers believe these differences may be great enough to warrant separate taxonomic status. To investigate the magnitude and nature of these differences with an independent data set, we sequenced a 867 base pair DNA fragment of the mitochondrial genome that includes half of the ND4 gene and three tRNA genes. We obtained sequence data from 30 individuals of V. rosenbergi drawn from across its range in southern Australia, and also included representatives of two other Varanus species, V. gouldii and V. varius. Thirteen mitochondrial haplotypes were found among the 30 V. rosenbergi samples. Phylogenetic signal in the data sets was strong and a variety of phylogenetic analyses of the data all resulted in the same single fully resolved tree. The differences observed between populations of V. rosenbergi are not considered great enough to support the description of new taxa, but are sufficient to clearly define five evolutionary significant units, one of which is comprised of the threatened NSW/ACT populations.